Novel polymers and their use in photographic applications



United States Patent ABSTRACT OF THE DISCLOSURE A photographiccomposition comprising interpolymers having (1) units of acrylic acid,(2) units of monomer represented by the formula:

where R is a hydrogen atom or methyl group and R is an alkyl radicalwith (3) units of monomer having the formula:

where R is a hydrogen atom or alkyl group, R and R are each divalentsaturated aliphatic hydrocarbon radicals and R and R each representhydrogen atoms or alkyl groups; wherein said interpolymer comprises upto by Weight, of said (1), at least about 75%, by weight, of said (2)and up to about 10%, by weight, of said (3).

This invention relates to novel interpolymers of acrylic acid,unsaturated carboxylic acid esters and sulfobetaines. More particularly,this invention relates to the use of such interpolymers in photographicsilver halide compositions. In a specific aspect, this invention relatesto photographic elements which contain said novel interpolymers in atleast one layer.

Gelatin is generally used in the preparation of photographic silverhalide emulsions because of its good dispersing properties and itsexcellent protective colloid properties. However, gelatin is susceptibleto dimensional change when subjected to varying temperature or humidityand like conditions. Various natural and synthetic materials have beenproposed as substitutes for gelatin in one or more layers of aphotographic element to provide dimensional stability. However, many ofthese materials will salt-out, i.e., coagulate, in the presence oforganic or inorganic salts which are often present in photographicsilver halide compositions. It is evident, therefore, that a substitutefor gelatin which combines improved dimensional stability with good salttolerance will greatly enhance the art.

Accordingly, it is an object of this invention to provide a polymer ofacrylic acid, an unsaturated carboxylic acid ester and a sulfobetainewhich polymer exhibits a desirable combination of physical properties.

Another object of this invention is to provide novel and improvedphotographic compositions.

A further object of this invention is to provide novel interpolymerswhich can be used in photographic applications and which resistcoagulation or salting out in the presence of inorganic or organicsalts.

Another object of this invention is to provide novel polymer dispersionswhich are particularly useful in photographic applications.

A further object of this invention is to provide photo- Patented Nov.19, 1968 "ice graphic elements comprising a photographic silver halidelayer and, incorporated in at least one layer of said photographicelement, interpolymers of acrylic acid, unsaturated car'boxylic acidesters and sulfobetaines.

A still further object of this invention is to provide photographicsilver halide emulsions in which at least a part of the 'binding agentfor the silver halide comprises a novel interpolymer as describedherein.

Other objects of the invention will become apparent from an examinationof the specification and claims that follow.

In accordance with the invention, the above objects are attained withfilm forming interpolymers of (1) up to about 15%, by weight, of acrylicacid, (2) at least about by weight, of a monomer having the formula:

where R is hydrogen or methyl and R is an alkyl radical, desirablycontaining 1-12 carbon atoms ,with (3) up to about 10%, by weight, of amonomer having the formula:

Where R is hydrogen or alkyl, R and R are each divalent saturatedaliphatic hydrocarbon radicals, desirably containing up to 12 carbonatoms and R and R are each hydrogen or alkyl.

The novel interpolymers of this invention are excellent substiutes forgelatin in photographic applications since they exhibit not onlyexcellent salt tolerance in the form of latices or dispersions, but theyalso exhibit excellent dimensional stability, photographic inertness,water insolubility and water permeability. In addition, these copolymersexhibit good compatibility with gelatin which makes it possible toreplace only a small part of the gelatin in a photographic composition,depending upon the particular combination of properties desired.

A significant feature of this invention is that the properties whichmake the novel polymers of this invention suitable gelatin substitutesare very closely related to the concentration and nature of the monomersfrom which the novel polymers are prepared. For example, a significantincrease in acrylic acid content over that described herein gives apolymer which is soluble in water. This is undesirable in a gelatinsubstitute, particularly where it is to be used in unhardenedphotographic silver halide emulsions. Furthermore, a substantialincrease in the sulfobetaine content of the interpolymer results in aproduct which shows little or no compatibility with gelatin. Inaddition, the substitution of the alkyl acrylate or rnethacrylate withsuch closely related monomers as acrylonitrile results in hard, brittle,film-forming materials which are unsuitable as gelatin substitutes inphotographic silver halide emuls1ons.

As already indicated, the polymers described herein are prepared byinterpolymerizing acrylic acid, an unsaturated carboxylic acid ester anda sulfobetaine. The sulfobetaines employed in the preparation of theseinterpolymers include any of the sulfobetaines having the formula:

where R, R R R and R are each as defined hereinbefore. The R, R and Rradicals include any of the alkyl radicals and preferably contain up toabout 12 carbon atoms, often 1-8 carbon atoms, as exemplified by methyl,ethyl, propyl, pentyl, octyl, dodecyl and the like. The R and R divalentsaturated aliphatic hydrocarbon radicals can be branched or straightchain and will often contain up to 12 carbon atoms, as exemplified bymethylene, ethylene, propylene, 1,2-propylene, tetramethylene,1,3-isobutylene, pentamethylene, hexamethylene, octamethylene and thelike. The sulfobetaines include for example, 5,5, 10 trimethyl 9 oxo 8oxa 5 azonia undecene- 1 sulfonate, 4 t butyl 9 methyl 8 oxo 7 oxa 4-aza-9-decene-l-sulfonic acid, 4,4,9-trimethyl-8-oxo-7-oxa-4-azonia-9-decene-l sulfonate and the like.

The sulfobetaines can be prepared using any method known to be suitablefor this purpose. A convenient method for preparing the sulfobetainemonomers comprises reacting the appropriate amino alkyl ester of anunsaturated carboxylic acid with the appropriate sultone. Such areaction can be carried out in the presence of an organic solvent suchas acetonitrile, a liquid hydrocarbon or a ketone such as acetone attemperature up to about 100 C., preferably 50 to about 80 C. In general,the reaction is complete in less than 8 hours, often in about 2 to about6 hours. The reaction is not pressure dependent and thereforesuperatmospheric or subatmospheric pressures can be employed. Theresulting sulfobetaine can be isolated by conventional procedures. Thereactants are generally employed in stoichiometric concentrationsalthough slight excesses of either reactant can be employed. As isobvious to one skilled in the art the specific reaction conditions, forexample, temperature, pressure, and the like, will depend upon theparticular amino alkyl ester and sultone employed. Another suitablemethod for preparing the sulfobetaines, particularly where R and R inthe above formula are both hydrogen, is to react the appropriatehydroxyalkyl amine with the required sultone and then esterify withacrylic acid or a derivative thereof.

The interpolymers of this invention are prepared by copolymerizing atleast one sulfobetaine monomer, as described above, with acrylic acidand at least one ethylenically unsaturated acrylic ester having theformula:

where R is hydrogen or methyl and R is an alkyl radical. Suitable alkylradicals include, for example, ethyl, methyl, propyl, pentyl, dodecyland the like. Suitable monomers include for example, ethyl acrylate,methyl acrylate, butyl acrylate, ethyl methacrylate, octyl methacrylate,and the like. The interpolymers employed in practicing this inventioncontain, in polymerized form, up to about preferably about 5 to about15%, by weight, of polymerized acrylic acid, at least about 75%,preferably about 75 to about 93 by weight, of acrylate and/ ormethacrylate and up to about 10%, preferably about 2 to about 10%, byweight, of the sulfobetaine reactant. Such polymers are film forming andgenerally have an average molecular weight in the range of about 5000 toabout 500,000 or more.

The temperature at which the interpolymers of this invention areprepared is subject to wide variation since this temperature dependsupon such variable features as the specific monomers used, the durationof heating, pressure employed, and like considerations. However, thepolymerization temperature generally does"notexceed about 100 C., andmost often, is in the rangeof about 50? to about 90 C. Thepolymerization can be carried out in suitable solvents or diluents, forexample, water or mixtures of water with water miscible solvents, asexemplified by methanol, ethanol, propanol, isopropyl alcohol, butylalcohol, and the like. The pressure employed in the polymerization, ifany, is usually only suificient to maintain the reaction mixture inliquid form, although either su eratmospheric or subatmosphericpressures can be used. The concentration of polymerizable monomer in thepolymerization mixture can be varied widely with concentrations up toabout 40 percent, by weight, and preferably about 20 to about 40percent, by weight, based on the weight of vehicle being satisfactory.Suitable catalysts for the polymerization reaction include, for example,the free radical catalysts, such as hydrogen peroxide, cumenehydroperoxide, water soluble azo type initiators and the like. In redoxpolymerization systems the usual ingredients can be employed. Ifdesired, the polymer can be isolated from the reaction vehicle byfreezing, salting out, coagulation or by using other separationprocedures suitable for this purpose.

Dispersions of the photographic silver halide in the novel interpolymersof this invention, in combination with other binding agents, such asgelatin, can be made in a variety of ways. For example, an aqueousgelatin dispersion of the photographic silver halide can be mixed withan aqueous dispersion of the interpolymer. Alternatively, thephotographic silver halide can be precipitated in an aqueous dispersionof the interpolymer or other colloid. In this case, a water solublesilver salt such as silver nitrate is admixed wtih a water solublehalide such as potassium bromide in the presence of the mixture. Instill another procedure, the photographic silver halide is precipitatedin an aqueous gelatin solution and digested in the conventional mannerknown to the art. After digestion, but prior to coating, there is addedto the emulsion an aqueous dispersion of the interpolymer of thisinvention. The bulk of the resulting dispersions can be increased by theaddition of more of the interpolymer and/or natural or syntheticcolloids or binding agents suitable for use in photographic silverhalide emulsions. Satisfactory colloids include, for example, gelatin,colloidal albumin, cellulose derivatives, synthetic resins such aspolyvinyl compounds and the like.

The interpolymers of this invention can be employed in one or morelayers of a photographic silver halide element. However, theinterpolymers described herein do not exhibit the very good peptizingaction for silver halides shown by such binding agents as gelatin orother colloids. Therefore, photographic silver halide emulsions in whichthe interpolymers of this invention are used contain at least somebinding agent such as gelatin which exhibits the required peptizingaction. Generally, binding agents which comprise about 10 to about oftenat least 50%, and most often about 40 to about 65%, by weight, of thenovel polymers described herein, give good results in photographicsilver halide emulsions. In the preferred case, the remainder of thebinding agent is gelatin, although other colloids also give goodresults. As already indicated, where the polymers are used inphotographic elements in layers other than the emulsion layers, forexample, in filter layers, antihalation layers, antiabrasion layers,antistatic layers and barrier layers, they can be used as the solevehicle or in admixture with the natural or synthetic colloids mentionedabove. The silver halide employed in the preparation of light sensitivecoatings described herein includes any of the photographic silverhalides as exemplified by silver bromide, silver chloride and silveriodide, or mixed silver halides such as silver.

chlorobromide, silver bromoiodide, and the like.

The photographic compositions described herein can be coated on a widevariety of supports. Typical supports are cellulose nitrate film,cellulose acetate film, polyvinyl acetal film, polystyrene film,polyethylene terephthalate film and related films or resinous materialsas well as glass, paper, wood and the like. Supports such as paper whichare coated with a-olefin polymers, particularly polymers of a-olefinscontaining 2-10 carbon atoms as exemplified by polyethylene,polypropylene and ethylenebutene copolymers and the like can also beemployed.

The emulsions containing the novel interpolymers of this invention canbe chemically sensitized with compounds of the sulfur group, noble metalsalts such as gold salts, reduction sensitized with reducing agents, andcombinations of these. Furthermore, emulsion layers and other layerspresent in photographic elements made according to this invention can behardened with any suitable hardener such as aldehyde hardeners,aziridine hardeners, hardeners which are derivatives of dioxane,oxypolysaccharides such as oxystarch, oxy plant gums, and the like.

The emulsion can also contain additional additives, particularly thoseknown to be beneficial in photographic emulsions, including for example,stabilizers or antifoggants, particularly the water soluble inorganicacid salts of cadmium, cobalt, manganese and zinc as disclosed in U.S.Patent 2,829,404, the substituted triazaindolizines as disclosed in U.S.Patents 2,444,605 and 2,444,607, speed increasing materials,plasticizers and the like. Sensitizers which give particularly goodresults in the photographic compositions disclosed herein are thealkylene oxide polymers which can be employed alone or in combinationwith other materials, such as quaternary ammonium salts, as disclosed inU.S. Patent 2,886,437 or with mercury compounds and nitrogen containingcompounds, as disclosed in US. Patent 2,751,299.

The polymers of this invention can be used in various kinds ofphotographic emulsions. For example, they can be used in X-ray and othernon-spectrally sensitized emulsions as well as orthochromatic,panchromatic and infrared sensitive emulsions, particularly thosesensitized with merocyanine dyes, cyanine dyes, carbocyanine dyes andthe like. Furthermore, the polymers of this invention can be used inemulsions intended for color photography, for example, emulsionscontaining color forming couplers or emulsions to be developed bysolutions containing couplers or other color generating materials. Inaddition, these polymers can be used in emulsions intended for use indiffusion transfer processes which utilize the nondeveloped silverhalide in the non-image areas of the negative to form a positive bydissolving the undeveloped silver halide and precipitating it on areceiving layer in close proximity to the original silver halideemulsion layer. Such processes are described in Rott U.S. Patent2,352,014, Land U.S. Patent 2,543,181 and Yackel et al. U.S. Patent3,020,155. The novel polymers described herein can also be used in colortransfer processes which utilize the diffusion transfer of an imagewisedistribution of developer, coupler or dye from a light sensitive layerto a second layer while the two layers are in close proximity to oneanother. Color transfer processes of this type are described in YutzyU.S. Patent 2,856,142, Land et al. U.S. Patent 2,983,606, Whitmore etal. British Patents 904,364 and 840,731 and Whitmore et al. U.S.application Ser. No. 392,471, now Patent No. 3,227,552. Silver halideemulsions containing these polymers can be processed in monobathprocesses such as described in Haist et al. U.S. Patent 2,875,048 or instabilization type processes.

This invention can be further illustrated by the following examples ofpreferred embodiments thereof although it will be understood that theseexamples are included merely for purposes of illustration and are notintended to limit the scope of the invention unless otherwisespecifically indicated.

Example 1 As already indicated, the sulfobetaine monomers describedherein can be prepared by reacting an amino alkyl ester with a sultone.To illustrate, a solution of 12.2 g. (0.1 mole) of 1,3-propane sultoneand 15.7 g. (0.1 mole) of dimethylaminoethyl methacrylate and 100milliliters of acetonitrile is refluxed for two hours. The precipitatedproduct is separated from the liquid, washed with hot acetonitrile anddried in vacuum. 27.4 g. of white crystalline4,4,9-trimethyl-8-oxo-7-oxa-4-azonia-9-decene-l-sulfonate is obtained.

The sulfobetaine monomer can be interpolymerized with acrylic acid andunsaturated carboxylic acid esters to form novel interpolymers havinggood salt tolerance.

To illustrate, 375 ml. of distilled water is placed in a flask, heatedto C. and degassed with nitrogen. 3.9 ml. of Triton 770 1 (40%solution), 1.5 g. of potassium persulfate and 0.5 g. of sodium bisulfiteare then added in the order given. After the additions, the followingtwo solutions are added under nitrogen with vigorous stirring over aperiod of 12 minutes: (1) a solution of 107 g. of ethyl acrylate and 5.5g. of acrylic acid and (2) 3.9 ml. of Triton 770 (40% solution) and 12.5g. of 4,4,9 trimethyl 8 oxo 7 oxa 4 azonia 9 decenel-sulfonate, preparedas above, in 125 ml. of water. After the reaction mixture is stirred foran additional 30 minutes at 80 C. it is diluted to 10% solids withwater.

The latex obtained is highly resistant to coagulation in sodiumchloride, calcium chloride and triethyl amine hydrochloride salts. Toillustrate, the addition polymer latex does not precipitate upon theaddition of various salt solutions, including 10% aqueous solutions ofzinc acetate, cadmium chloride, barium chloride, magnesium sulfate,calcium chloride, sodium chloride and the like.

In contrast, a polymer which is prepared in the absence of thesulfobetaine monomers immediately precipitates upon exposure to thesesolutions. Thus, the aforementioned salt solutions all immediatelyprecipitate an aqueous dispersion of a copolymer of ethyl acrylate withacrylic acid (:5 by weight). Furthermore, when the ethyl acrylatemonomer is replaced with acrylonitrile the interpolymer forms a hard,brittle film which is not a suitable binding agent for photographicemulsions.

Example 2 Example 1 is repeated except that solution (1) comprises 15.4g. of acrylic acid and 138.6 g. of n-butyl acrylate. Upon testing in themanner described in Example 1, the emulsion obtained is shown to besignificantly tolerant to the presence of sodium chloride salts.

Example 3 The polymerization procedure described in Example 1 isrepeated using a catalyst system of 1.0 g. of potassium persulfate and1.2 g. of sodium dithionite. The sodium dithionite is supplied by thelatter of the following two solutions which are added simultaneouslyover a period of 11 minutes: (1) 15.8 g. of acrylic acid and 142 g. ofn-butyl acrylate, (2) 1.27 g. of sodium dithionite, 3.9 ml. of Triton770 (40% solution) and 8.3 g. of4,4,9-trimethyl-8oxo-7-oxa-4-azonia-9-decene-l-sulfonate in ml. ofwater. Excess potassium persulfate is removed from the emulsion bytitration with 10% sodium dithionite. The slight excess of sodiumdithionite is removed by heating. The catalyst free emulsion resistscoagulation when exposed to sodium chloride and organic salts such astriethylamine hydrochloride.

Example 4 A solution of 78.5 g. (0.5 mole) of N,N-dimethylaminoethylmethacrylate and 68.0 g. (0.5 mole) of 1,4-butane sultone and 250 ml. ofacetonitrile is refluxed for 1% hours during which time the sulfobetaineprecipitates. To the reaction mixture is added 200 ml. of diethyl ether.The product is isolated by filtration, washed and dried in vacuo. Thereis obtained 78.5 g. of 5,5,10trimethyl 9 oxo 8 oxa 5 azonia 10 undecene1- sulfonate (54% of theoretical yield).

Using the procedure of Example 1, 11.6 g. of acrylic acid, 104 g. ofn-butyl acrylate and 9. 4 g. of 5,5,10-tri methyl 9 oxo 8 oxa 5 azonia10 undecene 1- sulfonate are polymerized at 95 C. The latex, at pH 5.0,is stable to the addition of concentrated divalent cationic saltsolutions when tested as in Example 1.

Ti-iton 770 is a surfactant composition composed of a sodium alkyl arylpolyether sulfate and isopropanol, manufactured by Robin and Haas Co.

Example A solution of 55.6 g. (0.3 mole) of t-butylaminoethylmethacrylate and 36.6 g. (0.3 mole) of 1,3-propane sultone in 150 ml. ofacetonitrile is refluxed for 8 /2 hours. The solution is evaporated to aviscous oil which crystallizes upon addition of acetone. The product isseparated by filtration and dried in vacuo. Recrystallization fromethanol gives 28.6 g. of crystalline, solid 4-t-butyl-9-methyl-8-oxo-7-oxa-4-aza-9-decene-l-sulfonic acid.

The procedure of Example 1 is repeated with 16.0 g. of acrylic acid,142.2 g. of n-butyl acrylate and 8.3 g. of sulfobetaine monomer preparedusing the above procedure. The polymerization is carried out at 95 C. toform an emulsion interpolymer which, at pH 5, is stable to the additionof concentrated solutions of divalent cationic salts.

Example 6 The interpolymers prepared as described herein can be employedin photographic silver halide emulsions. To il- Example 7 The novelpolymers of this invention can be used in photographic silver halideemulsions without any substantial deterimental effect in photographicproperties even though there is a very desirable improvement indimensional stability and salt tolerance. To illustrate, a high contrastlitho type silver chlorobromoiodide gelatin emulsion containing 55millimoles (10.1 g.) of cadmium per mole of silver is coated onpolyethylene terephthalate film support with the following changes inbinding agent: Coating A contains 107 g. of gelatin per mole of silverand is coated at 456- mg. of silver and 451 mg. of gelatin per squarefoot; Coating B contains 40 g. of gelatin and 80 g .of the polymer (dryweight) contained in Example 2, per mole of silver and is coated at acoverage of 456 mg. of silver and 511 mg. of vehicle per square foot. Ina third composition, 80 g. per mole of silver of butyl acrylate-acrylicacid copolymer, 90:10 by weight, is added to an emulsion containing 40g. of gelatin per mole of silver. In this last case the cadmium salt inthe emulsion causes immediate coagulation of the butyl acrylate-acrylicacid copolymer so that the emulsion cannot [be coated on the support.

Samples of the films from Coatings A and B are exposed in an Eastman 1BSensitometer, developed for 3 /4 minutes in a hydroquinone-lowsulfite-ion developer such as Kodak D85, fixed, washed and dried. Thephotographic characteristics of the coatings are as follows CoatingRelative Speed Gamma Fog From the above table, it can be seen that thenovel interpolymers of this invention do not deleteriously effect thephotographic properties of photographic silver halide emulsionscontaining them.

Example 8 coated on a polyester support in the following order; (1) anunhardened gelatin layer (coverage 50 mg./ft. containing a conventionalantihalation dye and a butyl acrylate acrylicacid-4,4,9-trimethyl-8-oxo-7-oxa-4-azonia- 9-decene-l-sulfonateinterpolymer, as described herein (coverage 35 mg./ft. and (2) anunhardened galatino silver chlorobromide emulsion (coverage 260 mg.silver/ ft. 1130 mg. gelatin/ft?) and a hydroquinone tanning developingagent (coverage 110 mg./ft.

After exposure, the element is processed in the usual manner using thefollowing solutions SOLUTION A Activator Na CO -H O grams NaOH do 58 KBrdo 28 dissolved in one liter of water and used at room temperature,activation time thirty seconds to one minute.

SOLUTION B Tanning inhibitor Na SO grams" 50 dissolved in one liter ofwater, used at room temperature, treatment timethirty seconds.

SOLUTION C Acidifying solution Citric acid grams 50 NaCl do 50 dissolvedin one liter of water, usde at room temperature, treatment time-thirtyseconds.

The processed element is used to make a resist for a Gravure plate, asdescribed in Yackel US. Patent 3,148,063. The emulsion layer iscontacted against the wet metal surface and the polyester supportstripped away. The stripping layer is then removed with Warm water.

Thus, by the practice of this invention there is obtained novelinterpolymers which exhibit an excellent combination of properties whichmake them particularly useful in photographic silver halide emulsions.The photographic elements containing these interpolymers exhibitimproved dimensional stability and salt tolerance. The novelinterpolymers can be used as replacements for all or part of the usualbinding agents which are generally employed in photographic elements.For example, the novel interpolymers described herein can be used inphotographic silver halide emulsion layers, stripping layers, backinglayers, anti-abrasion layers and the like.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention as described hereinabove and as defined in the appendedclaims.

We claim:

.1. A photographic silver halide composition in which the binding agentcomprises an interpolymer of (1) units of acrylic acid, (2) units ofmonomer represented by the formula:

where R is a hydrogen atom or methyl group and R is an alkyl radicalwith (3) units of monomer having the formula:

where R is a hydrogen atom or alkyl group, R and R are each divalentsaturated aliphatic hydrocarbon redicals and R and R each representhydrogen atoms or alkyl groups; wherein said interpolymer comprises up 9to 15%, by weight, of said (1), at least about 75%, by weight, of said(2) and up to about 10%, by Weight, of said (3).

2. A photographic silver halide composition according to claim 1 whereinsaid film forming interpolymer is a terpolymer.

3. A photographic silver halide composition in which the binding agentcomprises a film forming interpolymer of (1) about to about 15%, byweight, units of acrylic acid, (2) about 75 to about 93%, by weight,units of an alkyl acrylate and (3) about 2 to about by weight, units ofmonomer having the formula:

where R is a hydrogen atom or an alkyl group, R and R are each divalentsaturated aliphatic hydrocarbon radicals and R and R each representhydrogen atoms or alkyl groups.

4. The photographic emulsion of claim 1 in which R in formula (2)contains 1-12 carbon atoms.

5. A photographic silver halide composition according to claim 1 whereinsaid binding agent comprises gelatin and at least 10%, by weight, ofsaid interpolymer.

6. A photographic silver chlorobromide emulsion in which the bindingagent comprises gelatin and at least 10%, by weight, of a film forminginterpolymer of (1) about 5% to about by weight, of units of acrylicacid, (2) at least about 75%, by weight, units of monomer having theformula:

where R is a hydrogen atom or a methyl group and R is an alkyl radical,with (3) about 2% to about 10%, by weight, units of monomer having theformula:

where R is a hydrogen atom or an alkyl group, R and R are each divalentsaturated aliphatic hydrocarbon radicals and R and R each representhydrogen atoms or alkyl groups.

7. A photographic silver chlorobromide emulsion in which the bindingagent comprises gelatin and at least 50%, by weight, of a film forminginterpolymer of (1) units of acrylic acid, (2) units of monomerrepresented by the formula:

ll CHFCII- OR1 where R is a hydrogen atom or methyl group and R is analkyl radical with (3) units of monomer having where R is a hydrogenatom or alkyl group, R and R are each divalent saturated aliphatichydrocarbon radicals and R and R each represent hydrogen atoms or alkylgroups; wherein said interpolymer comprises up to 15%, by weight, ofsaid (1), at least about 75%, by weight, of said (2) and up to about10%, by weight, of said (3).

8. A photographic silver halide emulsion in which the binding agentcomprises an interpolymer of (1) about 9%, by weight, units of acrylicacid, (2) about 83%, by weight, units of butyl acrylate and (3) about 8%units of 4,4,9-trimethyl-8-oxo-7-oxa-4-azonia-9-decene-l-sulfonate.

9. A photographic silver halide emulsion in which the binding agentcomprises an interpolymer :of (1) about 9%, by weight, units of acrylicacid, (2) about 83%, by weight, units of butyl acrylate and (3) about 8%units of 5,5,10-trimethyl 9 oxo 8 oxa-S-azonia-lO- undecene-l-sulfonate.

10. A photographic element comprising a photographic silver halide layerand incorporated in .at least one layer of said photographic element, afilm forming interpolymer of (1) units of acrylic acid, (2) units ofmonomer represented by the formula:

where R is a hydrogen atom or methyl group and R is an alkyl radicalwith (3) units of monomer having the formula:

where R is a hydrogen atom or alkyl group, R and R are each divalentsaturated aliphatic hydrocarbon radicals and R and R each representhydrogen atoms or alkyl groups; wherein said interpolymer comprises upto 15%, by weight, of said (1), at least about by weight, of said (2)and up to about 10%, by weight, of said (3).

11. A photographic element comprising a photographic silver halidelayer, and incorporated in at least one layer of said photographicelement, a film forming interpolymer of (1) about 5 to about 15 byweight, units of acrylic acid, (2) about 75 to about 93%, by weight,units of alkyl acrylate and (3) about 2 to about 10%, by weight, unitsof monomer having the formula:

where R is a hydrogen atom or an alkyl group, R and R are each divalentsaturated aliphatic hydrocarbon radicals and R and R each representhydrogen atoms or alkyl groups.

12. A photographic element comprising a photographic silver halide layersuperimposed upon a polyethylene terephthalate support, and incorporatedin at least one layer of said photographic element, an interpolymerof 1) units of acrylic acid, (2) units of monomer represented by theformula:

where R is a hydrogen atom or methyl group and R is an alkyl radicalwith (3) units of monomer having the formula:

where R is a hydrogen atom or alkyl group, R and R are each divalentsaturated aliphatic hydrocarbon radicals and R and R each representhydrogen atoms or alkyl groups; wherein said interpolymer comprises upto 15%, by weight, of said (1), at least about 75%, by weight, of said(2) and up to about 10%, by weight, of said (3).

13. A photographic element comprising a photographic silver halide layersuperimposed upon a polyethylene terephthalate support, and incorporatedin at least one layer of said photographic element, a film forminginter- 3,411,912 1 1 12 polymer of (1) about 5 to about 15%, by weight,units References Cited of acrylic acid, (2) about 75 to about 93%, byWeight, UNITED PA N units of alkyl acrylate and (3) about 2 to about10%, STATES TE TS by Weight, units of monomer having the formula:2,794,742 6/1957 Fowler et 96-87 0 2 5 2,839,401 6/1958 Gray et a1. 96114 XR g 1 FOREIGN PATENTS 561,082 10/1957 Belgium.

Where R is a hydrogen atom or an yl p, 1 and NORMAN G. TORCHIN, PrimaryExaminer. R are each divalent saturated aliphatic hydrocarbon 10radicals and R and R each represent hydrogen atoms or SMITH AmsmntExammer alkyl groups.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,411,912 November 19, 1968 Thomas K. Dykstra et a1.

It is certified that error appears in the above identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 2, line 31, "R should read R line 34, "substiutes" should readsubstitutes Column 7, line 38, before "per mole of silver" insertchloride same column in the table, fourth column, line 2 thereof, "0.1"should read .01 line 73, "layer:" should read layer Column 8 line 6,"galatino" should read gelatino line 30, "usde" should read used lines73 and 74, "redicals" should read radicals Column 9, lines 12 to 16, theformula should appear as shown below:

l cH =r'3-c-0-R -riIa-R -s0 same column 9, lines 62 to 65, the formulashould appear as shown below: fi 1'2 cH -O-R -IiI9-R -SO Signed andsealed this 10th day of March 1970.

(SEAL) Attest:

EDWARD MQFLETCHERJR. WILLIAM E. SCHUYLER, JR.

Attesting Officer Commissioner of Patents

